submarine explosion
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At least 18 people are believed to have been on board the submarine that caught fire, exploded and partially sank at the naval dockyard in Mumbai.

The blast happened on the INS Sindhurakshak around midnight and was shortly followed by a massive fire. Many of the sailors on board the submarine reportedly managed to jump off to safety, but more than a dozen are feared trapped inside the hull.

"There are some people who are trapped on board, we are in the process of trying to rescue them, we suspect it to be in the range of 18," navy spokesman PVS Satish told Reuters.

The vessel partially submerged after the fire. "We will not give up until we get to them," Satish added.

Fire brigades have been battling the blaze for almost 3 hours to prevent it from spreading to other vessels docked nearby.

Thus far authorities say the explosion was likely an accident.

INS Sindhurakshak is a 16-year-old Russian-made submarine which recently underwent an overhaul and upgrade, Indian media reported.